The present invention relates to an apparatus for shielding from the surrounding air a stream of molten metal being discharged from a discharge sleeve of a metallurgical vessel, particularly during the teeming of steel from a pouring ladle during an ingot casting operation.
It is known that problems arise frequently when attempting to prevent air from contacting and rejoining a discharge stream of molten steel, previously degassed by a vacuum treatment operation, and thereby to prevent nitrogen or oxygen from being again absorbed by such steel. Particularly when the molten stream is teemed in an ingot casting operation, i.e. into geometrically simple bodies in permanent molds, nothing prevents the molten steel, during its free fall from the pouring ladle into the sprue of the molds, from absorbing nitrogen, for example to an undesirably high content. A free air space between the ladle lip and the sprue, in the case of group teeming, or the mold in the case of a top pouring operation, cannot be avoided even if the ladle is placed with a high degree of precision into the pouring position. The height of such free air space may be as much as 80 to 150 mm.